A brake block holder often moves out of line with the brake actuator push rod acting thereon for brake application. Due to its normal suspension it will move along a circular line in the plane of the push rod axis, but sometimes it must also be laterally movable, which makes it necessary to find another solution than the simple type of transmission with a wedge engaging a groove as shown in GB No. 1,140,488.
For different reasons, for example the rough environment, it is also preferred to avoid any slippage between the different parts.